Summary of Comments and Responses on 

Revisions to Test Methods and Testing 

Regulations

Prepared June 2013

Proposed in the Federal Register on

January 9, 2012
(This page included to provide for two sided copying)
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TABLE OF CONTENTS

Section No. Page

1.0 Summary 2

2.0 List of Commenters 3

3.0 Public Comments and Responses 5
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1.0 SUMMARY

On January 9, 2012, the U.S. Environmental Protection 

Agency (EPA) proposed Revisions to Test Methods and Testing 

Regulations. This action promulgated technical and editorial 

corrections for source testing of emissions and operations. 

Inaccuracies and outdated procedures in the current testing 

provisions have been revised, and new alternatives that have 

been approved but not incorporated into the test procedures are 

being added. These revisions will improve the quality of data 

where they are being made and will give testers additional 

flexibility to use the newly approved alternative procedures. 
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2.0 LIST OF COMMENTERS

Item Number in 

EPA-HQ-OAR-2010-0114 Commenter and Affiliation

0005 Wayne Stollings

Triangle Environmental Services, Inc.

0006 Walter Smith

0007 Source Evaluation Society Newsletter

0008 Procedure for Determining Stratification at CEMS Locations

0009 Byron Nelson

Southern Environmental Sciences, Inc.

0010 Ed Juers III

0011 J.F. Jarrett

0012 Anonymous

0013 Anonymous

0014 Fred Ballay

New Jersey Dept. of Environmental Protection

0015 Kevin McGinn

URS Corporation

0016 Michael A. Klein

New Jersey Dept. of Environmental Protedtion

0017 Fred Ballay

New Jersey Dept. of Environmental Protection

0018 Fred Ballay

New Jersey Dept. of Environmental Protection

0019 Anonymous

0020 Ronnie Watkins

Alabama Dept. of Environmental Management

0021 Michael A. Klein

New Jersey Dept. of Environmental Protection

0028 Melvin E. Keener, Ph.D.

Coalition for Responsible Waste Incineration

0027 John S. Peterson

Delta Air Quality Services

0025 Brian J. Kearney 

GenOn Energy

0024 John S. Peterson
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Delta Air Quality Services

0026 John S. Peterson

Delta Air Quality Services

0023 David Elam

Summa Consultants, Inc.

0022 Thomas Maza

Michigan Dept. of Environmental Quality

0029 Barbara A. Walz

Tii-State Generation and Transmission Association, Inc.

0030 John H. Phillips

Ford Motor Company

0031 Barry Rayfield

RE2 Solutions, LLC

0032 Lauren E. Freeman

Hunton & Williams, LLP

0036 Shannon S. Broome

Katten Muchin Roseman, LLP

0035 Andrew Dicke

GE Energy

0039 Stephen R. Gossett

Eastman Chemical Company

0034 Alice Edwards

Alaska Dept. of Environmental Conservation

0038 Angus E. Crane

North American Insulations Manufacturers Association

0033 Cathe Kalisz

American Petroleum Institute

0040 Alice Alice Edwards

Alaska Dept. of Environmental Conservation

0037 Cathe Kalisz

American Petroleum Institute

0041 Susan M. Clark

Lubrizol Advanced Materials, Inc.

0042 Lauren E. Freeman

Hunton & Williams, LLP

0043 Lauren E. Freeman

Hunton & Williams, LLP

0044 Lauren E. Freeman

Hunton & Williams, LLP
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3.0 PUBLIC COMMENTS AND RESPONSES

Supportive Comments

1. Comment: Two commenters expressed appreciation for the 

agency's efforts to amend the rules to reflect advancements 

in test methods and increase flexibility in determining 

which method is appropriate for a given situation. One 

commenter believed the changes proposed would provide 

better data from source testing of emissions and operations 

for regulatory compliance determinations. (0030, 0031)

Response: No response is necessary.

Parts 60 & 75 Synch 

2. Comment: One commenter expressed appreciation for the 

clarity in requiring evaluation of cyclonic flow in all 

cases. The commenter recommended that the EPA make such 

revisions with an eye to the requirements of both Part 60 

and Part 75 test programs. For example, it was recommended 

that the stratification test procedures be harmonized as 

should the applicability of Method 205. Harmonization 

reduces the need for obtaining approval for case-by-case 

harmonization requests when test programs are undertaken to 

satisfy both Part 60 and Part 75 objectives. The commenter 

supported the information posted to the docket by commenter 

0007 and hoped that the EPA considers their arguments in 

making a final decision regarding stratification 

evaluation. (0023)

Response: We attempt to harmonize testing requirements in 

Part 60 with those in Part 75 as much as possible. In some 

cases, such as with Method 205, a method may lend itself to 

general use under one program but create challenges in 

established procedures in another program. 

3. Comment: A commenter noted that Part 75 regulations 

require bias and drift assessments for the reference 

methods after each relative accuracy test run. The 

commenter thought this procedure would more accurately 

assess performance than the proposed allowance to conduct 

the tests after a series of runs. The commenter believed 
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the Part 60 and 75 requirements should be the same because 

dual compliance is often the case. (0017)

Response: As much as possible, we attempt to write similar 

requirements under both parts. In some cases, however, the 

flexibilities allowed under Part 60 for showing compliance 

may not need to be as stringent as the Part 75 requirements 

due to the nature of the trading program. In cases of 

showing dual compliance, the most stringent requirement 

should be followed. 

Use of Mercury-Free Equipment 

4. Comment: Three commenters expressed approval for allowing 

alternatives to mercury containing thermometers and 

barometers for both the worker exposure concerns and 

environmental hazards associated with mercury. (0023, 0025) 

Response: No response is necessary.

5. Comment: A commenter felt the terms “equivalent in terms 

of performance” and “suitably effective” used in the 

proposal for alternative mercury-free equipment were 

ambiguous and vague and would lead to confusion and 

uncertainty. They suggested the language be modified to 

include the following: “If in the opinion of an 

established testing firm, having been in business for 3-

plus years, the alternative thermometer is equivalent in 

terms of performance or suitably effective, the mercuryfree thermometer may be used.”

Response: We do not believe the commenters suggested 

language added further clarity and the original language 

was not changed. 

Alternatives to AA Analysis

6. Comment: Two commenters supported the addition of 

inductively coupled plasma-atomic emission spectrometry 

(ICP-AES) and cold vapor atomic fluorescence spectrometry 

(CVAFS) as alternatives to atomic absorption (AA) analysis.

The commenters noted that many labs have been using ICP-AES 

for Method 29 for years and have a good established track 

record. Both commenters recommended that inductively 

coupled plasma-mass spectrometry (ICP-MS) be allowed as 

well for Methods 12, 104, and 108 since ICP-AES is becoming 

outdated and suffers from various inter-elemental 
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interferences. It was noted that ICP-MS also offers 

improved sensitivity and precision. By allowing both 

methods, a lab would have the flexibility to sort out any 

sample specific interferences and could provide better data 

quality than by using ICP-AES exclusively. (0030, 0031)

Response: We agree with the commenters. We have added ICPMS as an analytical option to Methods 12, 104, and 108.

Use of Tedlar Bag Alternatives

7. Comment: One commenter fully supported the allowance of 

other brands of films for sample bags but noted that the 

preamble was incorrect in stating that Tedlar bags are no 

longer being produced. The commenter indicated that Tedlar 

bag manufacturers were having difficulty obtaining Tedlar 

film in early 2011 due to minimum order restrictions 

imposed by one Dupont distributor. However, Dupont has 

actually increased PVF resin production to meet increased 

Tedlar film demand for use in solar panels, and other 

distributors are still selling Tedlar film to bag

manufacturers to support the stack testing and industrial 

hygiene communities. 

The commenter noted that some bag manufacturers may not 

have the resources to make the suitability determinations 

for specific applications on alternative bag materials. It 

may be more appropriate to indicate in the application that 

either the tester, the bag manufacturer, or the film 

manufacturer should determine the applicability of Tedlar

equivalent materials for the compound of interest (prior to 

use of the alternative material for source testing). The 

commenter also felt it appropriate to include a provision 

in each method that this information be made available for 

review by the administrator over any test program where the

alternative sampling bag material is to be used. (0031)

Response: We thank the commenter for this clarifying 

information on the availability of Tedlar and the need to 

verify applicability. We will state in the affected methods 

that alternative bag materials must be verified for their 

suitability for the compound of interest by the 

manufacturer and this verifying information should be made 

available for inspection. 
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8. Comment: A commenter supports the EPA’s proposed changes 

to allow for the use of sampling bags made from materials 

other than Tedlar. (0033, 0037)

Response: No response is necessary.

Use of Method 320 as an Alternative to Other Methods

9. Comment: A commenter supported the use of Method 320 as an 

alternative in various applications in most cases. However, 

the commenter noted that in recent independent audits of 

test programs where Method 320 was used for reactive 

compounds, there have been cases where testing firms 

provided inadequate documentation to confirm the method was 

properly followed. It was suggested that Method 320 be 

amended to include a required QA/QC reporting section so 

any reviewer or administrator is provided with adequate 

information to confirm the results are correct. 

The commenter noted that in past experience, test reviews 

have shown such deficiencies as inadequate sampling 

equipment and that recovery checks have failed to detect 

bias that should have been obvious. It was noted that the 

design and materials of construction for a sample 

introduction system feeding gases into an FTIR are critical 

to successful sampling with this method, and recent data 

suggest this method needs to be strengthened so all 

sampling biases are thoroughly taken into account and 

documented when the method is used for certain reactive 

gases (NO, NO2, SO2, SO3, HF, etc.). (0031)

Response: The commenter’s suggestions are appreciated but 

are beyond the scope of the proposed use of Method 320 as 

an alternative method. These suggestions will be retained 

and will be considered in the next methods update package.

Method 201A

10. Comment: Several commenters had questions about the 

isokinetic requirements in Methods 201A. We understand that 

the EPA intends to reduce the number of allowable traverse 

point isokinetic values outside of the 80 to 120 percent

range from five to two. One commenter recommended that, 

instead of reducing the number of allowable traverse point 

values outside the acceptable range from five to two, the 

EPA should reduce the number of traverse points above 120

percent to two and place no restrictions on the number of 
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traverse points below 80 percent. Traverse points below 80 

percent introduce a bias to higher-than-true emissions. The 

commenter felt sources should be allowed to accept this 

bias and not incur the cost of another test run. This 

proposed alternative approach that allows for additional 

isokinetic values less than 80 percent would simplify 

testing, especially for sources operating near ambient 

temperature where the allowable range in flow rates needed 

to achieve the cut sizes for both the PM10 and PM2.5 cyclones 

is very small. It was believed to be very difficult to 

satisfy both the cyclone cut size requirements and the 

isokinetic requirements for low temperature sources. (0015, 

0032, 0033, 0037)

Response: We believe the commenter has misinterpreted the 

requirements for isokinetic flow in Method 201A. The 

criteria are not changed from the version of Method 201A

published in 1990. The intent of this section in the method

is to allow more than two points outside the range when 

more than 12 traverse points are sampled. The EPA disagrees 

with the commenters request to degrade the sampling quality 

if the source is the one that is disadvantaged. The intent 

of our test methods is to obtain emissions measurements of 

known accuracy and precision. If the stack tester believes 

that poor quality is acceptable if it results in a high 

bias, then they should justify this in their test plan 

description of the data quality objectives, date quality 

indicators and the assessment of the use of the collected 

test data. It is then up to the regulatory authority to 

decide whether to accept the test for compliance 

determination or require that the test be conducted again.

11. Comment: A commenter noted that Section 7.2.1 allows 

0.0001% (1 ppmw) residue in the acetone blank, but then 

later says this is the same as 0.1 mg/100 ml. It is not. It 

should be 0.1 mg/100 g. 1 ppmw would be equal 0.079 mg/100 

ml. This same error can be found in Method 202 Section 

7.2.1. Similarly, Method 202, Section 7.2.2 for the hexane 

blank residue should be in the units mg/g and not mg/ml. 

1.0 ppmw would be 0.065 mg/100 ml at 1 ppmw for hexane. 

Method 202, Section 7.1.3 also has the same unit confusion 

for the water blank, but since the specific gravity is 1, 

it works out to be the same value. (0021)

Response: The EPA acknowledges the error and has made the 

appropriate corrections in the method.
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12. Comment: Section 11.2.1 implies that when the temperature 

of the exhaust gas is not greater than 85oF, then the 

procedures in Method 17 are sufficient for quantifying 

condensable PM. However, a note in the section for filter 

analysis (Method 5 Section 11.2.4) allows the filter and 

wash solution to be heated above 85oF. A commenter asked 

that the temperature requirement for condensable PM filters 

should be clarified. They suggested changing the note in 

Section 11.2.1 to read “In-stack filter samples collected 

at 30°C (85°F) may include both filterable insoluble 

particulate and condensable particulate. For these samples,

the nozzle and front half wash and filter may not be heated 

above 30°C (85°F). They should be desiccated then weighed, 

but not extracted since insoluble particulate will not be 

recovered from the extraction.” (0022)

Response: The commenter is correct that Method 17 filter 

analysis refers to Method 5 Section 8.2 and there is 

confusion about applying the subsequent sections of Method 

5, (specifically the alternative offered in Section 11.2.4 

of Method 5). We have adopted the suggested change (with 

minor revisions).

13. Comment: One commenter questioned the proposed requirement 

to conduct the preliminary traverse as close as possible to 

the anticipated testing time on sources that are subject to 

hour-by-hour gas flow rate variations of approximately ± 20 

percent and/or gas temperature variations of approximately 

± 10°C (± 18°F). The commenter noted that Method 201A 

requires calculation of new delta ΔH values for points 

where temperatures are 28°C (50°F) above the average. It 

thus appears that the proposed revision would inadvertently 

“correct” the wrong temperature. The commenter recommended 

the following language: “Conduct the preliminary traverse 

as close as possible to the anticipated testing time on 

sources that are subject to hour-by-hour gas flow rate 

variations of approximately ± 20 percent and/or gas 

temperature variations of approximately ± 28°C (± 50°F).” 

(0035)

Response: We agree with the commenter that Section 8.7 of 

Method 201A requires use of the appropriate ΔH when the 

stack temperatures vary by more than 28 C (50 F). We have

revised the text in Section 8.3.4.1 to be consistent and 

indicate that preliminary traverse is conducted as close as 

possible to the anticipated testing time on sources that 

are subject to hour-by-hour gas flow rate variations of 
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approximately 20 percent and/or gas temperature variations 

of approximately 28 C ( 50 F).

14. Comment: Two commenters recommended that the EPA make a 

change to the Method 201A description that is not listed in 

the January 9, 2012, Federal Register. The particle sizeefficiency curves for the PM10 and PM2.5 cyclones should be 

presented as an additional figure. This information will 

allow developers of future methods or sampling equipment to 

compare the performance of different cyclones with the 

specified cyclones in Method 201A. (0037, 0033)

Response: We recognize that technical information 

requested by this commenter would help equipment 

manufacturers develop alternative equipment that meets the 

method specification. However this information is not 

necessary to implement the method correctly. Therefore, we

plan to provide this additional technical reference on our 

website as a frequently asked question. 

15. Comment: A commenter objected to the flagging of data not 

meeting the constant weight requirement and reporting these 

data as a minimum value. This was believed to be acceptable 

for emission estimates but unacceptable for compliance 

demonstration. For compliance demonstrations, the method 

should not require the reporting of values that are below 

the detection limit of the methodology. (0029, 0032)

Response: We disagree with the commenter because of their 

misunderstanding of the method requirements. This issue is 

not about minimum detection limits as indicated by the 

commenter. The tester should have developed data quality 

objectives that incorporated their capabilities for 

measuring a mass that was quantifiable and comparing this 

capability limit with the applicable limit for the source. 

The tester would then establish a minimum sample volume to 

meet quantifiable limits at the standard level. The 

resulting sample duration to meet the minimum sample volume 

would insure that they would have a mass above their 

minimum mass that would demonstrate compliance.

Rather, the issue addressed in the method involves how to 

handle measurable mass when the constant weight criteria 

cannot be met, as may be the case with hydroscopic 

particulate matter. If the case arises where the sample 

gains weight while it is being weighed and the constant 

weight criteria cannot be met, then reporting the final 
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weight with a data quality flag provides an opportunity for 

the regulatory authority and the facility to understand 

that there may be a quality issue with the data related to 

a compliance demonstration that needs to be evaluated. 

16. Comment: A commenter notes that in the formula for 

“Sampling Rate Using Only PM2.5 Cyclone” in Eq. 8, 

the constant “0.060639” is off by a factor of 10 which 

increases the estimated Qs used for the pretest 

determinations. The formula found in “Application Guide for

Measurement of PM2.5 at Stationary Sources” (Eq. 5B-28) uses 

“6.0639 x 10-3” and gives a better estimation of the Qs for 

use in pretest determinations. (0024)

Response: We acknowledge and thank the commenter for this 

observation and will correct equation 8 in Method 201A.

Method 202

17. Comment: Two commenters thought the revisions to the 

nitrogen purging procedure were unclear. One noted that the 

revised language conflicted with the current language for 

impinger configurations. The other commenter felt the 

revisions could lead to inadvertent errors. They 

recommended that the revised text be clarified to indicate 

that the long stem impinger should not be the first 

impinger after the cooling coil during the test run. It 

should be clearly noted that the long stem impinger is used 

only during the purging step. Sample gas contact with the 

condensed water in this impinger would contribute to 

increased formation of artifact sulfates and other oxidized 

compounds formed from dissolved gases. (0026, 0037, 0033)

Response: The commenters are correct that the empty 

impinger(s) are part of the Method 202 condensable 

particulate collection equipment. The revision referred to 

in this comment was rewritten to clarify the text in 

Section 8.5.3.1 regarding sample purging after the sample 

is collected. This revision does not change the 

configuration, number, or contents of the impingers used to 

collect samples. In Section 8.5.3.1 of Method 202, if one

chooses to conduct a pressurized nitrogen purge on the 

complete Method 202 sampling train, they may simplify the 

purge process by quantitatively transferring the water 

collected in the condenser and the water dropout impinger 

into the backup impinger as an alternative to replacing the 

short stem with a short stem insert in the knockout 

impinger prior to purging the sampling train. In this case,
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the water combined in the backup impinger must be measured 

and the resulting volume or weight recorded to be included 

as part of the moisture collected during sampling as 

specified in Section 8.5.3.4. This simplification 

eliminates the need to purge the condenser and knockout 

impinger contents since they are quantitatively transferred 

to the backup impinger that is already equipped with a long 

stem impinger stem. We have reworded the revisions to 

clarify the intent.

18. Comment: A commenter notes that, although efforts have 

been made to minimize SO2 absorption in the Method 202 

condensate, the potential for SO2 bias still exists, 

especially when the gas being sampled has high moisture 

content. In the commenter’s discussions with the EPA, it 

was indicated that, if condensate is accumulating in the 

first impinger, then the tester can stop the test run, 

remove the condensate, continue on with the test (having 

performed all the required leak-checks), and begin purging 

the removed condensate. The commenter asked that the EPA 

add this option if it is indeed an acceptable means of 

dealing with condensate in the first impinger. (0032)

Response: The EPA recognizes and agrees with the need to 

minimize gas contact with the moisture collected in the 

Method 202 knockout and backup impinger. Section 6.1.2 of 

the method puts no restriction on the size of the knockout 

impinger for this method. If high moisture condenses and 

accumulates to overwhelm the capacity of the knockout 

impinger or if sufficient moisture condenses in the backup 

impinger to rise above the impinger tip, then the test run 

may be stopped or interrupted to take corrective action.

19. Comment: A commenter pointed out that the “<” sign shown 

in the temperature range of the water bath should be 

removed. (0032)

Response: This correction has been made.

§60.8 Cyclonic Flow and Gas Stratification

20. Comment: Two commenters expressed concern for the 

stratification testing and cyclonic flow testing 

requirements proposed for the Part 60 General Provisions 

and Method 1. They felt the proposed changes would affect 

the needed sampling equipment, time to prepare and conduct 

the test program, and the associated costs. Such costs 
15

could include installing sampling platforms at cyclonicfree locations, modifying the stack and upstream control 

equipment to eliminate cyclonic flow at the existing 

sampling location, or use of an alignment approach to 

measure the emissions. Most sources have very few options 

for sampling alternative test locations. Depending on the 

scale of the equipment and the materials of construction 

required, it was believed these modifications could cost an 

additional $50,000 to $250,000 more. Use of the alignment 

approach would increase the on-site testing time by 

approximately 50 percent.

The commenters did not believe the proposal preamble 

provided technical justification for the need to eliminate 

cyclonic flow in sources being tested for gaseous 

emissions. Method 1 was believed to already include 

sufficient requirements for addressing cyclonic flow in 

obtaining the gas flow rate data needed to calculate mass 

emissions based on the concentration data.

It was not clear whether methods with separate lab analyses 

such as Methods 18 and Method 26 could practically follow 

the proposed requirements. On-site analyses on a point-bypoint basis would be needed, and this would significantly 

increase the cost of the test program. A stack testing 

consultant estimated the cost per three run test could 

increase by approximately $1,000. One commenter desired the 

proposed changes be handled separately from the other 

proposed test revisions. Both commenters felt that changes 

to these requirements should be based on a cost impact 

analysis and non-confidential, readily reviewable data 

demonstrating the need for this change. One commenter 

recommended the EPA withdraw the proposed changes from the 

present rulemaking until this is done. (0037, 0033)

Response: The commenters are justified in requesting a 

separate rulemaking for the proposed stratification and 

cyclonic flow revisions. We have withdrawn these revisions 

from the final rule and will address them in a separate 

subsequent rulemaking.

21. Comment: The General Provisions include the requirement 

for evaluations of gas stratification and cyclonic flow 

with all compliance tests. This seems overly burdensome. 

Initial checks for both should be adequate as long as there 

are no modifications to the process. (0020, 0032)
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Response: See the response to Comment 21. Cyclonic flow 

and gas stratification will be addressed in a subsequent 

rulemaking.

22. Comment: A commenter believed the narrative added to check 

for cyclonic flow and emission gas stratification was 

unclear and inconsistent with subsequent requirements in 

the section. They recommended we revise to the following 

language: “An owner/operator should take reasonable steps 

to ensure that sampling locations are free of cyclonic flow 

and flue gas stratification. If other procedures are not 

specified in the applicable subpart to the regulations, use 

the appropriate procedures in Method 1 to check for 

cyclonic flow and Method 7E to evaluate emission gas 

stratification and selection of sampling points." (0029, 

0032)

Response: See the response to Comment 21. Cyclonic flow 

and gas stratification will be addressed in a subsequent 

rulemaking.

23. Comment: Two commenters noted that Section 60.8(h), Method 

1, and Method 7E all have instructions/guidance and changes 

relative to selection of sampling points. It is not clear 

which approach is to be implemented for any given situation 

and the descriptions proposed in Methods 1 and 7E differ in 

a critical fashion. For example, the proposed language in 

Method 7E contains a caveat for low concentrations and 

temporally varying sources that is not contained in the 

Method 1 language. Additionally, the Method 1 language for 

the alternative point selection for the stratification 

check contains an additional criterion for using the three

points that is not present in either the old or proposed 

Method 7E. One commenter recommended that requirements for 

the point selection criteria be streamlined and clarified 

in a single location, and that all other methods or 

specifications reference the chosen location; failing that,

the commenter recommended that clarifying language be added 

to clearly indicate the stratification approach to be used. 

It was also unclear as to how a stratification test, in the 

case of a non‐instantaneous gaseous measurement, was to be 

performed. If, for example, only Method 26 was being 

performed to determine HCl concentration, a stratification 

test using the pollutant would require a separate sample 

train located at each point of interest, and analysis then 

performed which would of course be time and cost 

prohibitive. (0015, 0022)
17

Response: See the response to Comment 21. Cyclonic flow 

and gas stratification will be addressed in a subsequent 

rulemaking.

24. Comment: A commenter believes that cyclonic flow is not an 

issue for gaseous pollutant measurements and that no 

special procedures should be required for those pollutants 

regardless of the level of cyclonic flow. (0032)

Response: See the response to Comment 21. Cyclonic flow 

and gas stratification will be addressed in a subsequent 

rulemaking.

25. Comment: A commenter objected to the proposed addition to 

60.8(h) which requires each test location to be verified to 

be free of cyclonic flow. The commenter notes that some 

amount of yaw and pitch angle are almost always present in 

utility stacks or ducts. The new proposal fails to 

acknowledge that under applicable procedures, like the one 

in Method 1, some level of cyclonic flow is acceptable 

without the use of special procedures, and even where the 

degree of cyclonic flow is deemed unacceptable, 

measurements can still be made using alternative 

methodologies. The commenter believed a requirement that 

sources be free of cyclonic flow would warrant a reproposal 

discussing and quantifying the impact of the change on 

existing sources to Part 60. (0032)

Response: See the response to Comment 21. Cyclonic flow 

and gas stratification will be addressed in a subsequent 

rulemaking.

26. Comment: A commenter suggested that current 60.8(e)(1)(ii) 

be revised to say “the owner/operator must attempt to 

provide...” rather than “the owner/operator shall provide” a 

stack or duct free of cyclonic flow during performance 

tests. The commenter suggested alternative language for 

revising 60.8 that would be clearer than the proposed 

language and would list alternative procedures for testing 

when cyclonic flow was deemed significant enough to affect 

measurements. The language would also note that 

stratification testing need only be performed one time at 

the source if no physical changes have been made that would 

alter stratification patterns. (0032)
18

Response: See the response to Comment 21. Cyclonic flow 

and gas stratification will be addressed in a subsequent 

rulemaking.

27. Comment: A commenter asked that the EPA address 

stratification requirements in a consistent manner. There 

are currently stratification testing requirements in 

Methods 1, 7E, and 30A, Performance Specification 2, and 

Appendix A of Part 75, all with their own nuances. (0029)

Response: See the response to Comment 21. Cyclonic flow 

and gas stratification will be addressed in a subsequent 

rulemaking.

28. Comment: A commenter encouraged the EPA to develop a 

stand-alone stratification method. Currently, there are 

stratification testing requirements in Methods 1, 7E, 30A, 

Performance Specification 2, and Part 75, all with their 

won nuances.

Response: See the response to Comment 21. Cyclonic flow 

and gas stratification will be addressed in a subsequent 

rulemaking.

29. Comment: A commenter cautioned the EPA not to use 12 

points as a “default” number of traverse points for 

stratification tests. In many cases, a larger or smaller 

number of points need to be used in order to collect a 

representative sample. 

Response: See the response to Comment 21. Cyclonic flow 

and gas stratification will be addressed in a subsequent 

rulemaking.

30. Comment: A commenter pointed out that Method 1 does not 

specify the frequency of stratification testing and 

cyclonic flow determination (i.e. one-time test, before 

each test event, etc.). (0032)

Response: See the response to Comment 21. Cyclonic flow 

and gas stratification will be addressed in a subsequent 

rulemaking.

31. Comment: A question was asked relative to the proposal’s 

acknowledgement that a stratification test may not be 

meaningful at sources with temporally variable or low 

emissions. The commenter asked that the EPA give a method 
19

of demonstrating temporal variation and identify the 

concentration that would qualify a facility as a lowemission source and exempted from the stratification test. 

For temporal variation, it was suggested that a reference 

probe could be used to demonstrate that the process 

variability at an individual point is consistently varying 

by more than 10 percent over a specified period of time 

(e.g., every 10 minutes). At sources where concentrations 

are low, diluent measurements could be used instead for the 

stratification test. (0032)

Response: See the response to Comment 21. Cyclonic flow 

and gas stratification will be addressed in a subsequent 

rulemaking.

§60.8 Method 205

32. Comment: A commenter supported the allowance to use Method 

205 for field instrument calibration. However, it was 

supported only for methods where protocol gases are not 

readily available. The commenter acknowledged that 

calibration gas dilution systems may be necessary for some 

reference methods (e.g., those for mercury or HCl), but 

felt the added potential sources of error associated with 

these dilution systems should not allow their use for most 

common methods (e.g., Methods 3A, 6C, 7E, 10, 20, and 25). 

(0032)

Response: Method 205 was written with tight performance 

criteria to minimize sources of error. We believe the 

benefit of reducing the number of gas cylinders necessary 

for a test is worth allowing Method 205 as a calibration 

option.

§60.8 Audit Samples

33. Comment: A commenter believes Methods 30A and 30B should 

be added to the list of methods for which audit samples 

are not required to validate performance test results.

Method 30A should be exempted because it is an 

instrumental method. The final rule language for adopting 

the audit sample provisions was cited as stating that it 

is necessary to require audit samples for those test 

methods that use instruments to measure pollutants in 

stack gas samples taken directly from an emission source

because they already have sufficient calibration and 
20

quality assurance requirements that would make an 

additional audit sample redundant.

Method 30B should be exempted from the audit requirement 

because it already contains measures sufficient to verify 

data acceptability. The commenter noted the requirement 

that laboratories demonstrate acceptable recovery from the 

chosen sorbent media through a bias test of spiked 

sorbents, use of paired trains to show precision and verify 

data acceptance, and field recovery tests to verify the 

sampling and analytical approach.

Response: We agree with the commenter and will add Methods 

30A and 30B to the list of methods not requiring audit 

samples.

§60.13 

34. Comment: A commenter recommended that the first sentence 

in the proposed clarification of 60.13(d)(1) be further 

clarified by revising the phrase “at least once daily” to 

“at least once each operating day.” (0029, 0032)

Response: The recommended revision has been made.

35. Comment: For 60.13(h)(1), a commenter supported allowing 

6-minute averages to be based on fewer than 36 equallyspaced data points as proposed. Requiring the use of 36 

equally spaced data points would result in invalid 6-minute 

averages during each calibration and maintenance period. 

(0032)

Response: No response is necessary.

Subpart Db

36. Comment: A commenter supported the EPA’s proposed change 

to Part 60, Subpart Db regarding the use of calibration 

dilution systems as allowed by Method 205 of 40 CFR Part 

51, Appendix M. This change increases the flexibility for 

conducting test programs and potentially reduces the safety 

hazards inherently involved in handling and transporting 

compressed gas cylinders. The commenter also supported the 

proposed allowance to use Method 320 for SO2 and NOx 

monitoring. This proposed change also provides increased 

test program flexibility. (0037, 0033)
21

Response: No response is necessary.

Subpart JJJJ

37. Comment: A commenter objected to Method 320 being allowed 

for determining total VOC’s in Subpart JJJJ because its

results as the method is written are not comparable with 

those from Method 25A. If Method 320 remains as an 

alternative to Method 25A, adequate testing procedures 

should be included to ensure that the data generated from 

both methods are comparable. This should include a list of 

compounds that must be included in the sample analysis and 

procedures for determining detection limits. The option for 

using propane response factors should be removed. If Method 

320 is used for determining VOC concentrations, the results 

should be reported as actual VOC’s and not as propane since 

there is no valid way to determine a theoretical propane 

response factor. (0020)

Response: The commenters request is beyond the scope of 

this rulemaking since we are not proposing to add Method 

320 to Subpart JJJJ. This comment will be evaluated for 

consideration in the future methods update rule. 

Engines Testing

38. Comment: A commenter noted that in removing Methods 1/1A 

from Subpart JJJJ in favor of sampling from the exhaust 

centroid, the mass based allowable option would still 

require Methods 1/1A for determining the number of sample 

points for measuring flow. Regarding flow measurements, 

Methods 2 and 19 are listed as options but Method 2C should 

be added to this list. Regarding Method 19, this method is 

problematic because it would require fuel monitoring to 

determine the stack flow, and the regulation does not 

specify accuracy requirements for fuel monitors. Similarly, 

for NSPS – Subpart IIII, removing Methods 1/1A requirements 

in determining the number of sample points for gaseous 

parameters does not take into account the same issues above 

for sample location and flow measurements because this 

regulation also requires determining particulate compliance 

using Method 5, which in turn requires Methods 1/1A. (0016)

Response: The requirement for use of Method 1/1A for 

determination of sampling points will be removed for NOx and 

CO measurement only. Method 1 or 1A will still be required 
22

for flow rate and particulate traverse point determination. 

Since Method 2C is the appropriate method for determining 

flow in small stacks, it will be added as an option to 

Method 2.

39. Comment: Three commenters agreed with the proposal to 

eliminate the requirement to use Methods 1 or 1A for sample 

point selection in Subparts IIII and JJJJ and instead to 

allow the use of single point sampling at a centroid 

location. (0025, 0033, 0037)

Response: As explained in more detail in response to 

Comment 41 below, the requirement to use Method 1 or 1A for 

sample point selection for gaseous pollutants/diluents has 

been removed from Subparts IIII and JJJJ and single point 

sampling at a centroid location will be allowed for ducts 

six inches or less in diameter. Ducts measuring more that 

six inches in diameter will need to be sampled at more than 

one point or tested for stratification.

40. Comment: A commenter noted that some requirements for 

Method 1 and 1A remain in Table 7 of Subpart IIII. These 

references to Methods 1 and 1A should be removed. (0033, 

0037)

Response: Table 7 of Subpart IIII will be clarified to 

require Method 1 or 1A only for PM determination.

41. Comment: In Subpart IIII, Table 7 applies to compression 

ignition engines with a displacement of greater than or 

equal to 30 liters per cylinder. A commenter believed this 

type of stationary engine should be equipped with sampling 

ports and have a stack diameter sufficient for 

stratification checks. In addition, since engine 

manufacturers of such large units typically use catalytic 

controls to comply with the large engine NSPS standards, 

there is an additional contribution to gaseous emission 

stratification from control variation across the catalyst 

bed outlet. It is unlikely such a unit would have a stack 

diameter of less than twelve inches. Therefore, the 

commenter recommends that the EPA not remove the 

requirement to use Method 1 or 1A for Subpart IIII engines. 

For NSPS Subpart JJJJ and NESHAPS Subpart ZZZZ, the 

commenter concurs that for very small diesel and spark 

ignition engines, a centroidal approach could be warranted. 

However, the commenter recommended that for an engine with 

a functional stack diameter of four inches or greater, it 
23

is reasonable and appropriate to retain a requirement to 

use Method 1 or 1A to check for stratification. (0034)

Response: The commenter makes two important points, first 

that stratification could potentially be introduced by 

catalytic controls and, second, that there is likely a 

significant population of internal combustion engines 

subject to at least one of the three subparts (Subparts 

IIII and JJJJ in Part 60 and Subpart ZZZZ in Part 63) that 

have exhaust stacks greater than 12 inches in diameter,

which could reasonably be sampled at multiple points. Based 

on these considerations, we refined the approach for 

sampling port location/sample point selection for gaseous

pollutants/diluents to be consistent across the three 

subparts that require performance testing of internal 

combustion engines to (1) allow single point sampling of 

the smallest ducts, (2) allow simplified three-point 

sampling of the mid-sized ducts, and (3) require a more 

extensive traverse or stratification testing of the largest 

ducts that do not meet the minimum Method 1 port location 

criteria. More specifically, the final rule will allow 

ducts less than or equal to six inches in diameter to be 

sampled at a single point at the centroid of the duct. 

Ducts greater than six but less than 12 inches in diameter 

will need to be sampled at three specified traverse points 

unless they have been demonstrated to be unstratified 

according to Method 7E. For ducts equal to or greater than 

12 inches in diameter, if the sampling port location meets 

the minimum Method 1 criterion for distance from 

disturbances (such as catalyst beds), they may be sampled 

at three points; the two stack diameter distance downstream 

from the nearest disturbance will provide for gas mixing 

and, coupled with a three-point traverse, yield a 

representative sample. If they don’t meet the Method 1 

criterion for distance from disturbances, ducts equal to or 

greater than 12 inches in diameter will be subject to 

stratification testing for determination of sampling 

points. 

Method 1

42. Comment: The revision to Method 1 would state "The test 

for the presence or absence of cyclonic flow would be 

required for all tests instead of recommended at sites 

suspected of having cyclonic flow." Commenters asked if

cyclonic flow checks are now required on rectangular 

stacks? (0011, 0032)
24

Response: See the response to Comment 21. Cyclonic flow 

and gas stratification will be addressed in a subsequent 

rulemaking.

43. Comment: The requirement to perform a cyclonic flow check 

for every testing event seems overly burdensome. An initial 

check for cyclonic flow during the initial performance test 

should be adequate, unless modifications are made to the 

process that would affect the gas flow characteristics of 

the stack gases. Documentation should be available on site 

during subsequent testing. (0035)

Response: See the response to Comment 21. Cyclonic flow 

and gas stratification will be addressed in a subsequent 

rulemaking.

44. Comment: A commenter asked that Section 11.2.2, which 

currently addresses non-particulate velocity traverses, not 

be revised to address non-particulate velocity gaseous 

traverses. The commenter noted that gaseous traverses are 

not required for non-isokinetic volumetric flow 

measurements, nor can the number of points for a velocity 

traverse be determined by a gaseous stratification test.

Gaseous concentrations are impacted by stratification 

(i.e., variations of concentration across the duct), while 

velocity measurements are affected by cyclonic or turbulent 

flow). The commenter recommended the EPA include in the 

proposed new Gaseous Traverse section a provision for 

performance testing similar to Method 7E, Section 8.1.1 

such as: For performance testing of continuous emission 

monitoring systems, follow the sampling site selection and 

traverse point layout procedures described in the 

appropriate performance specification or applicable 

regulation (e.g., Performance Specification 2 in appendix B 

to this part). In addition, the alternate criteria for 

gaseous traverse point concentration (i.e., +/- 0.5 ppm and 

+/- 1.0 ppm) must include the alternate criteria for nonppm diluent concentrations for oxygen and carbon dioxide 

from Method 3A (+/- 0.5 percent and 0.3 percent). Oxygen 

and carbon dioxide are ordinarily referenced in percent. 

(0035)

Response: See the response to Comment 21. Cyclonic flow 

and gas stratification will be addressed in a subsequent 

rulemaking.
25

45. Comment: Commenters noted that in the captions for Figures

1‐1 and 1‐2, the words upstream and downstream appear to be 

reversed. The distance from the sampling point upstream to 

the flow disturbance should be Distance B, and the distance 

from the sampling point downstream to the flow disturbance 

should be Distance A. (0015, 0035)

Response: The commenters are correct, and the recommended 

correction has been made.

Method 2

46. Comment: A commenter notes that in the Section 12.1 

nomenclature, the EPA proposes correcting the variable 

Ts(abavg), while equations 2-7 and 2-8 of §12.6 are not 

proposed to be updated. The EPA should update the equations 

substituting Ts(abavg) for Ts(abs). (0035)

Response: We have updated the equations as well as the 

nomenclature as the commenter requested.

Method 3C

47. Comment: A commenter offered an alternate calibration 

method consisting of triplicate analyses of an initial 

three or four part calibration extending through the 

applicable range of components similar to that of Method 25 

and Method 25C. The average response of each level of 

calibration is used to develop a linear calibration curve. 

A daily calibration analysis is performed in at least 

duplicate before the analysis of samples the average of 

which is compared to the initial calibration and accepted 

if the response factor for each component is within 20

percent of the initial calibration value, thus creating a 

continuing calibration curve. A second daily calibration is 

performed following the analysis of a set of samples or 

within 24 hours, whichever is shorter, to determine 

analytical drift. If the post analysis calibration is 

within five percent of the initial daily calibration, the 

analyses are acceptable. (0005)

Response: This suggested calibration procedure is a good 

one and is already allowed under current Method 3C. No 

method revision is needed.
26

Method 4 

48. Comment: A commenter commended the EPA for allowing Ffactors to determine moisture in Method 4 but pointed out 

the following issues with the way the procedure is written.

1. In the equation for BF, the value for “W” is used in two 

places; however, there is not an explanation or equation 

for determining “W”. If “W” is a calculated value, an 

equation for calculating it should be included. If it is 

not calculated, then information should be provided for 

determining the value of “W”.

2. RH% is included in the nomenclature but is not used in 

any equation. If the RH% is to be used for calculating BWs, 

then it should be added to the appropriate equation. 

3. The term “T” usually indicates absolute temperature. Is 

this correct in this case?

4. The equation for calculating BA includes the value “T”. 

According to the nomenclature, “T” can be expressed in 0F or 

0C. The value calculated for BA will be different depending 

on what units are used for ambient temperature. They are 

not interchangeable without changing the constants in the 

equation. It can’t be 0F and 0C.

5. Pbar is included in the nomenclature but is not shown in 

any of the equations. If the value for PB is intended to be 

used to calculate BWs, then it should be included in the 

appropriate equation. (0020)

Response: The term W is defined as the percent free water 

by weight. The term RH% was inadvertently left out of the 

equation for BA as a printing error. The units of the term T 

are in oF. The alternate units of oC have been deleted. The 

term Pbar is used in the calculation of BA and was 

inadvertently left out of the equation in the proposed rule 

due to a printing error. 

49. Comment: Two commenters supported the proposed changes in 

Method 4 to allow methods other than Method 4 to determine 

the moisture content of a gas stream. One commenter noted 

the missing term (% RH/100Pbar) in the BA calculation in the 

proposed notice. An incorrect placement of the minus sign 

after the parenthesis instead of before it in the exponent

of the equation was also brought to our attention. (0033, 

0037)
27

Response: The missing term in the proposed notice is an 

inadvertent printing error. The placing of the minus sign 

has been corrected as noted.

Method 5

50. Comment: Method 5 states that “mention of stopcock grease 

for air‐tight impinger seals would be deleted since it is 

outdated and not often used”. A commenter noted that his

firm, as well as others, routinely use stopcock grease to 

seal the impingers when performing Method 5 tests. The 

newer style impingers with O‐rings can be used when required 

for certain types of tests where analysis of the impinger 

liquid is performed. However, it was much easier for the 

commenter to use the standard ball and socket when a 

variety of impingers of slightly varying heights (as a 

result of purchases from various sources and numerous 

repairs over the years) are used in a particulate-only 

test. The ball with O‐ring combination does not work well at 

all if the impinger heights vary substantially. The 

commenter asked that we leave the reference to stopcock 

grease in the method.

Response: We disagree with the reasons from the commenter 

to not support the removal of stopcock grease from Method 

5.

51. Comment: A revision to Method 5 states “the use of a 

Teflon filter holder would be allowed without having to 

obtain the Administrator’s approval first”. It was unclear 

to a commenter whether the Teflon refers to the actual 

filter holder or the filter support or both. They noted 

that the use of a Teflon filter support should definitely 

be allowed without having to obtain the Administrator’s 

approval first. They felt Method 8 should also include a 

statement that the use of a Teflon filter support as well 

as a Teflon probe liner would be allowed, within certain 

temperature guidelines, without having to obtain the 

Administrator’s approval first. The Teflon filter support 

can be much more thoroughly and easily cleaned than the 

glass frit. Florida DEP has previously provided guidance 

allowing the use of the Teflon liners within certain 

temperature guidelines (less than 3500F) based upon 

discussions with the EPA’s Emission Measurement Center. 

(0009)
28

Response: We will clarify the language to refer to the 

filter holder support or frit only. We appreciate the 

additional comment for support of the use of Teflon liners 

in Method 5, but it is outside the scope of the proposed 

rule. We will consider the change in the next methods

update package.

52. Comment: During a February 7, 2012, webinar presented by 

the EPA, it was stated that Method 5 would be updated to 

indicate that negative filter catches would count as "zero" 

in determining the sample catch. However, this is not 

reflected in the proposal. It should be, and not just for 

Method 5, but for all methods that include filter catches. 

Negative filter catches would be an indication of not 

properly preparing the filters prior to sampling, as 

specified in the methods. Excessive negative catches could 

be an indication of improper/incomplete sample recovery 

and/or lost samples. A maximum negative catch value should 

be listed whereby the data would have to be flagged as 

qualified/compromised in the test report. (0016)

Response: We appreciate the comment for a prescriptive 

handling procedure of negative gravimetric catches, but it 

would be outside the scope of the proposal. We will 

consider the change in the next method update package.

53. Comment: The acetone maximum blank residue allowance 

currently in Method 5 is less restrictive by a factor of 10 

than the Method 201A and Method 202 allowances. Given that 

Method 5 is being used to measure similar low emission 

levels as Methods 201A/202, the blank residue allowances in 

Method 5 should be the same as those in Methods 201A/202. 

(0016)

Response: We appreciate the comment for changing the 

acetone blank allowance, but it would be outside the scope 

of the proposal. We will consider the change in the next

method update package.

54. Comment: For Method 5, Section 6.1.1.5, the use of Teflon 

filter holders is being added. This change is supported as 

long as truly leak-free Teflon holder assemblies are 

available. Additionally, the wording in this section of the 

docket refers to the entire holder being made of Teflon. It 

is my understanding the original proposal for this change 

was to allow for using the PTFE filter supporting “frit” 

developed by Thomas Thompson in 1987, intended originally 
29

for use with BIF methods, and Methods 23, 26A, 29, etc. 

(i.e.: a Teflon frit combined with the standard 

borosilicate glass inlet and outlet components). Since 

glass holders combined with the Teflon support frit is

likely the most common filter holder configuration in use 

with stack testing currently, please consider including the 

necessary wording allowing the use of either alternative in 

a filter housing arrangement. (0031)

Response: We will clarify the language to refer to the 

filter holder support or ‘frit’ only. 

55. Comment: For Method 5, Section 6.1.1.9, the current 

alternative test method using the Isostack metering system 

is proposed to be added within the method (instead of the 

original alternative test method). Since the original 

components of the Method 5 metering system go back at least 

40 years, there seems to be strong support in the testing 

community for allowing modern, and potentially more 

accurate, metering systems that can provide equivalent or 

better data quality. Will the EPA continue to initially 

issue alternate test methods as other metering systems 

become available and are approved for use? Or once 

performance data for an alternative metering systems is 

provided, will the EPA simply issue acceptance or 

equivalency letter to the manufacturer for an alternative 

metering system, citing this modified section in Method 5? 

(0035)

Response: We are not finalizing the reference to the 

Isostack metering system. We will continue to issue broadly 

applicable alternative method determinations or letters of 

assessment as to whether equipment meets intent of the 

method to the manufacturers.

56. Comment: One commenter was concerned that the EPA’s 

allowance of the Isostack metering system if the flow rate 

calibration does not deviate by more than five percent 

while requiring a two percent stability for other 

acceptable systems. The commenter believed that 

specifically allowing one manufacturer’s product, while

holding others to a different standard, provides an unfair 

business advantage and prevents fair competition in the 

marketplace for future development. (0029, 0032)
30

Response: We are not finalizing the modification to 

Section 6.1.1.9 that references the Isostack metering 

system.

57. Comment: In Section 7.1.3 of Method 5 regarding water, the 

EPA proposes adding a specification for water if it will be 

used for other analyses. One commenter believed the EPA 

should change this section to refer to the water 

specifications contained in the applicable method for 

performance of the additional analyses. Another commenter 

believed a maximum blank water residue of <0.001% is less 

restrictive by a factor of 10 to the residue allowance in 

Method 202. (0016, 0035)

Response: We agree with the commenters and will revise the 

language to refer to the water specifications required by 

the applicable method for additional analysis.

58. Comment: A single-point post calibration procedure of 

temperature sensors was proposed for Section 10.4 (Probe 

Heater Calibration). A commenter thought the procedure 

should be placed in Section 10.5 because it deals with 

temperature sensors, rather than in Section 10.4. (0035)

Response: We have made the appropriate change in the final 

rule.

59. Comment: A commenter supported the proposal of alternative 

method Alt-009 to Section 16.3 for the field calibration 

check of the metering system. The commenter did not believe 

this alternative should require the second leak-check 

procedure in Section 16.3.1.2 and described in Section 

10.3.1.1. The leak-check described in Section 10.3.1.1 is 

intended for systems with diaphragm pumps, and requires a 

wet test meter to accomplish. Sampling systems may use 

other type of pumps, such as a vane pump, that do not 

exhibit the same problem with the detection of leaks 

between the meter and the pump. In addition, this leak test 

was thought to defeat the purpose of a field calibration as 

it requires a wet test meter which is not typically 

available in the field. It was recommended that the method 

specify that the leak-check described in Section 10.3.1.1 

is only required for diaphragm pumps. Additionally, the 

following alternative metering system and pump leak check 

procedure was recommended for the final rule:

“First disconnect the static-side manometer tubing at the 

orifice. Then close-off the orifice outlet and the orifice 
31

static-side port using two small rubber stoppers. Apply and 

hold a positive pressure at the meter inlet. If the 

pressure as displayed at the incline manometer does not 

drop, then the metering system and pump can be considered 

leak-free.” (0035)

Response: We agree with the commenter and will revise the 

language in the final rule to use the procedures in 8.4.1.

60. Comment: A commenter recommended the EPA clarify the 

proposed acetone blank collection procedures stated in 

Section 8.7.5. As written, it is possible to interpret the 

proposed change as requiring two separate acetone blanks: 

the acetone storage bottle and the acetone-containing wash 

bottle. The commenter felt the change would increase the 

laboratory costs associated with Method 5 if it is the 

EPA’s intention to require two acetone blanks. The 

commenter believed the increased cost should be considered 

by the EPA when determining if this requirement provides 

any additional benefit to the testing process. (0033, 0037)

Response: We will clarify the language to note that only 

one reagent acetone blank is required from the storage 

bottle used in the cleanup.

61. Comment: In the revision to Section 6.1.1.7 to recheck the 

temperature sensor at one point after each test, a 

commenter recommended that each test be defined as a single 

testing event. This would allow for testing to be completed 

on more than one unit during a single mobilization. (0029, 

0032)

Response: We disagree with the recommendation due to the 

lack of supporting data for the allowance.

62. Comment: A commenter recommended we clarify which 

temperature sensor must be in “direct contact with the 

sample gas.” Should it be the probe or filter box 

temperature? It was noted that the filter temperature 

sensor is generally not in direct contact with the sample 

gas, but rather is located within the heated filter box. A 

misapplication of the specification would require 

significant modifications to existing equipment and make 

the majority of filter holders in service today obsolete. 

(0029, 032)
32

Response: We disagree with the commenter. The EPA revised 

Method 5 on October 17, 2000, (65 FR 61744) to require the 

measurement of the filtration temperature with a 

temperature measurement involving direct contact of the 

sample gas after the filter. We are revising the language 

to clarify that requirement and provide for an allowance 

for a glass, teflon or SS thermowell as well as for a 

second thermocouple for the control of the heated filter 

box temperature.

Method 5E

63. Comment: A commenter supported the allowance to use the 

Tekmar-Dohrmann analyzers using the single injection 

technique as an alternative to the Rosemont Model 2100A. 

The commenter noted that there are no known problems with 

this new alternative, and it provides greater flexibility 

in conducting tests in a variety of different circumstances 

and conditions and with multiple testing firms. 

Response: No response is necessary.

Method 6C

64. Comment: Two commenters believed the proposed interference 

analyses procedures as written for Method 6C would be 

difficult to conduct. It was not clear why the interference 

data would be relevant if the gas stream is stratified with 

oxygen and/or carbon dioxide concentrations varying by 

substantially more than 1 percent volume. The modification 

did not appear to be practical for all sources. The 

requirement to compile interference data for concentrations 

of O2 and CO2 within 1 percent volume of the stack 

concentration should be modified to require interference 

data applicable to be within 1 percent volume of the 

averages of the O2 and CO2 concentrations in the stack gas 

stream. (0033, 0037)

Response: For years, Method 6C has contained this 

requirement and there has been little protest from testers 

or manufacturers. The provisions were deleted from Method 

6C in 2010 when the instrumental source methods were 

updated because we believed the analyzer technology has 

advanced beyond the need for quenching correction. 

However, based on discussions with manufacturers and 

testers, the quenching effects of oxygen and carbon dioxide 

still present significant effects that should be corrected. 
33

At sources where it is impractical to handle the 

interference through matching of calibration and sample

matrices, other alternatives such as the use of nomographs 

are allowed.

65. Comment: Commenters did not think quenching poses a 

significant issue with extractive fluorescence system and 

suggested the quenching provisions be removed. They 

believed it unreasonable and expensive to maintain an 

adequate stockpile of calibration gases to satisfy the 

requirement that calibration gases be within 1 percent of 

the absolute oxygen and carbon dioxide stack content. They 

believed the added provisions would reduce the incentive to 

use analyzers affected by quenching and would result in 

testing delays and unreasonable costs. The commenter felt 

that, if required, the EPA should develop a quenching check 

procedure specific to the type of source and that a single 

check per specific analyzer should be enough.

(0029, 0032)

Response: See the response to Comment 64.

Method 7E

66. Comment: A statement is being added to Method 7E noting 

that the stratification test is not required at sources 

with temporally varying emissions. This was unclear to one 

commenter who asked if the source's emissions are 

temporarily varying why not wait and test when the 

emissions are stable? (0011)

Response: This statement has been dropped and is not in 

the final rule. We will evaluate means of determining 

stratification where emissions are temporally varying and 

address them in a future rule.

67. Comment: Two commenters believed that instrument quenching 

should be specifically addressed in Method 7E. Quenching 

has long been known to be a problem with both fluorescence 

and chemiluminescence based analyzers. This proposal 

returns the necessary quality assurance to address 

quenching back into Method 6C, but not in Method 7E. Some 

NOx analyzers are optimized to greatly minimize the 

quenching problem but all analyzers are not created 

equally. One commenter believes the analyzers that do not 

handle the problem well are largely flying under the radar 

and causing emissions to be under reported. The commenter 
34

knew of at least one current chemiluminescence-based 

analyzer where the manufacturer indicates special 

calibration methods must be used to account for the effects 

of quenching if CO2 concentrations exceed 0.5 percent. Due 

to the inconsistent design of the analyzers, the commenters 

believed Method 7E should include procedures to check the 

analyzers for the effects of quenching. These checks were 

not felt to be needed for every test but could be done at a 

minimum after the analyzer has been repaired or modified or 

on another periodic basis. The simple fix would be to 

require a periodic check at about 4 percent and 12 percent 

CO2 at a mid-range concentration for each analyzer range 

which is commonly used. (0014, 0018)

Response: The commenters raise valid concerns that have 

been addressed. Method 7E now requires a check for 

quenching prior to use of the analyzer and at two levels of 

CO2 after each repair, modification, or other periodic 

basis.

68. Comment: A commenter felt the inclusion of a Method 7E 

stratification check in Method 1 was confusing since Method 

1 is primarily used for velocity measurements. (0016)

Response: The proposed requirement that all tests be 

evaluated for gas stratification and cyclonic flow 

following Method 1 has not been included in the final rule. 

See the response to Comment 21.

69. Comment: Two commenters asked that the language in Section 

7.1.1 of Method 7E be amended. One commenter felt that 

pollutant emissions, especially carbon monoxide, could vary 

over a wide range during a test run. In this case, if a 

single range analyzer is used with sufficient span to 

quantify peak emissions, then the average concentration of 

the emissions may be less than 20 percent of the high level 

gas. The commenter suggested we add “To the extent 

possible” to 7.1.1 so it reads: ... To the extent possible,

choose this high-level concentration so that emission 

measurements will be within 20 to 100 percent of this 

concentration. The other commenter asked that the sentence 

be deleted since it could cause confusion and the 

measurement range and the exception for low-level 

concentration are already addressed in Section 3.4. (0022, 

0035)
35

Response: The noted sentence has been dropped from Section 

7.1.1 since the information is already addressed in Section 

3.4.

70. Comment: A commenter expressed support for the requirement 

that system bias and calibration error checks be based on 

the amount of time it takes for the measured concentration 

to increase to 95 percent or 0.5 ppm of the stable response 

and not necessarily of the certified concentration. This 

was believed to represent the actual response time of the 

system more accurately. (0032)

Response: No response is necessary.

71. Comment: A commenter felt the proposed changes to section 

8.2.5 of Method 7E would reduce the precision and accuracy 

of the response time determination. The change requires 

that the response time be recorded after the concentration 

reading has reached 95 percent or within 0.5 ppm of a 

stable response for the gas instead of after reaching 95 

percent of the certified gas concentration as in the 

current method. This change was proposed to allow the 

system bias to be taken into account before the response 

time reading is recorded and to conform the section to 

Section 8.2.6. The commenter noted that this will require 

response time to be determined retrospectively because the 

value of the stable response cannot be known until well 

after the time when 95 percent of the step change (upscale 

or downscale) was reached. Data stored by a data logger 

would have to be examined, but data loggers typically store 

only one-minute averages of data sampled during a given 

minute because of data storage limitations. Under the 

proposed revision, response time would not be determined 

with a precision better than to the nearest minute. System 

response to a step change is rapid for about the first 80

percent of the change, slow between 80 percent and 90

percent of the change, and even slower for the last 10

percent of the change, as response asymptotically 

approaches a stable value. Therefore, response time 

determined to the nearest minute under the proposed 

revision could be biased high by up to one minute. This 

will increase sampling times without providing any benefit. 

In contrast, the current procedure for determining response 

time is both more accurate and more precise than the 

proposed revision. The analyzers are calibrated immediately 

before measuring response time, so responses to low-level 
36

and to upscale gases should be very close to their 

certified concentrations. Therefore, 95 percent thresholds 

calculated from the upscale gas concentration should be 

very close to 95 percent of the final stable responses, and 

response time determined using those thresholds should be 

accurate. Furthermore, since the values of 95 percent

(upscale) and 5 percent (downscale) of the certified highlevel concentration are known before the response time test 

is started, the current procedure permits response time to 

be determined with a precision of up to the nearest second. 

The proposed revision would have been suitable decades ago 

when analog strip-chart recorders were used, which 

permitted an accurate, precise determination of response 

time retrospectively from a paper chart. However, the 

proposed revision is poorly suited for use with modern data 

loggers, which keep a permanent electronic record of data, 

but which are generally restricted to storing one-minute 

average data because of data storage limitations. The 

commenter felt that Section 8.2.6 should be worded to 

conform to the existing wording in section 8.2.5. (0039) 

Response: The revision to allow the response time 

determination to be recorded at less than 95 percent of the 

certified gas concentration should not be less accurate or 

precise than the current requirement. The revision does not 

prevent using the 95 percent of gas concentration for the 

response time endpoint if so desired. The revision only 

gives relief to systems that need up to the 5 percent bias 

limit to be able to meet the specification in a reasonable 

timeframe. In most cases, the continuous instrumental 

readout should be sufficient for determining response time 

without having to consult the retroactive data. In systems 

where this is not practicable, response times must be 

computed using minute-averaged data.

Method 8

72. Comment: A commenter noted that the 100 ml aliquot from 

Container 2 for SO2 analysis in Section 11.2.2 is a typo and 

should be 10 ml. (0032)

Response: The commenter is correct. This typo has been 

corrected. 

Method 10
37

73. Comment: Two commenters expressed their support of EPA’s 

proposed changes to allow for the use of sampling bags made 

from materials other than Tedlar. (0033, 0037)

Response: No response is necessary.

Method 10A and 10B 

74. Comment: A commenter asked that the use of canisters for 

sampling be allowed in Methods 10A and 10B as is the case 

for the modification to Method 10. (0005)

Response: The sampling and analysis procedures in Methods

10A and 10B are designed specifically for using a Tedlar 

bag. These procedures and equipment would have to be 

modified to accommodate canisters. Canisters should be an 

acceptable alternative to bags in this case, however, 

redesigning the method to accommodate canisters is beyond 

the scope of this rulemaking. The use of canisters will be 

addressed in the next methods update rulemaking. In the 

meantime, you may request the use of canisters as an 

alternative method to Methods 10A and 10B through the 

alternative methods option allowed under 40 CFR 60.8(b)(3).

Method 11

75. Comment: Two commenters supported the proposed changes to 

Method 11. They noted that parties concerned about possible 

depletion of the absorbing solution can comply with the 

proposed requirements simply by adding an additional 

impinger. (0033, 0037)

Response: No response is necessary.

Method 18

76. Comment: A commenter pointed out a typographical error in 

Section 8.2.1.1.2 of Method 18. The end of the probe should 

be at the centroid of the stack or not closer to the side 

walls than 1 inch, not 1 meter (1 m). (0031)

Response: The commenter is correct and this typographical 

error has been corrected.

Method 23
38

77. Comment: A commenter cited a number of exceptions made on 

the EPA Emission Measurement Center website allowing Method 

23 without the use of dichloromethane as a recovery 

solvent. The commenter applauded the removal of this 

solvent, from both a safety and shipping perspective, and 

recommended we consider making this change in Method 23 

itself. (0015)

Response: The commenter’s suggestion is appreciated but is 

beyond the scope of the proposed revisions to Method 23. 

These suggestions will be retained and will be considered 

in the next methods update package.

78. Comment: Method 23 specifies, in Section 4.2.3, that the 

condenser coil be recovered in the same manner as the 

connecting line. A commenter’s understanding was that the 

connecting line soak is based on the nature of Teflon, and 

the possibility of cold‐spots in the heated line. The 

commenter didn’t think these issues apply to the condenser. 

They recommended we clarify this intention for the 

condenser rinse. (0015)

Response: The commenter’s suggestion is appreciated but is 

beyond the scope of the proposed revisions to Method 23. 

These suggestions will be retained and will be considered 

in the next methods update package.

79. Comment: A commenter believed Method 23 should be modified 

to address the counting of Estimated Maximum Possible 

Concentrations (EMPCs) in determining total dioxins/furans. 

They noted that, in many cases, testers and labs count 

EMPCs as zero in determining totals. By EPA direction, if 

the source (facility) includes EMPCs in the total reported 

for dioxins/furans and is still in compliance with the 

emission limit, then the results can be accepted. If the 

source includes EMPCs in the total reported for 

dioxins/furans and is above the emission limit for total 

dioxins/furans, it may be because of a positive 

interference. However, the interference cannot be 

quantified and this interference will prevent the lab 

results from meeting the quality assurance requirements for 

identifying and quantifying their results. In this case, 

the only option would be for the laboratory to re-analyze 

the sample if they archived a sample fraction, or repeat 

the test. The re-analysis would involve re-cleaning the 

sample to remove the interfering substance. (0016)
39

Response: The commenter’s suggestion is appreciated but is 

beyond the scope of the proposed revisions to Method 23. 

These suggestions will be retained and will be considered 

in the next methods update package.

Method 24

80. Comment: A commenter recommended that 40 CFR 60.17 be 

further revised. The revision to Method 24 of Appendix A-7 

references only ASTM Method D2369 and not the specific 

sections of the method (since the section numbers may 

change with periodic updates). However, entry (34) in 

paragraph 60.17 (Incorporation by Reference) restricts the 

use of ASTM D2369 to the 81, 87, 90, 92, 93 and 95 specific 

revisions. The commenter strongly recommended that 

paragraph entry (34) of 60.17 also be revised to include 

the most current version of ASTM D2369, namely D2369-10e1. 

(0030)

Response: Section 6.2 of Method 24 lists the versions of 

ASTM Method D2369 that are acceptable in Method 24. This 

listing is the same as in 60.17 versions. Subsequent 

references to D2369 in the Method 24 instructions do not 

include the year listings.

Method 25 

81. Comment: One commenter asked that trap capillary lines be 

allowed in conjunction with in-stack filters in inlet 

sampling to control devices during destruction and removal 

efficiency (DRE) testing only where the temperatures of the 

inlet sampling location exceed approximately 121oC. This 

would prevent the negative bias which can occur due to the 

sample gas stream being cooled, which in turn can cause 

loss of organic compounds in the probe and filter 

assemblies. As this is the inlet to a control device, the 

possible particulate matter would still be a portion of the 

loading and as such should be included in the sample. 

Sources with naptha-based solvents, for example could 

suffer significant losses of organic loading due to the 

cooler glass fiber filter. This would not be applicable to 

OUTLET monitoring due to the overlap between organic and 

particulate measurements causing a potential double 

counting. (0005)

Response: We disagree with the commenter that this is a 

broadly applicable change that needs to be made to Method 
40

25. Since the comment refers only to destruction and 

removal efficiency (DRE) and only to inlet measurements at 

these tests, we recommend the commenter pursue a site 

specific alternative method approval process described on 

the EPA’s website at http://www.epa.gov/ttn/emc/guidlnd/gd022r3.pdf.

Method 25C

82. Comment: A commenter recommended the proposed nitrogen 

correction for dilution be added to Method 3C instead of 

Method 25-C because the raw data for Method 3C may not be 

available for the Method 25C analysis. This commenter and 

another recommended the dilution correction include the 

optional correction for oxygen for those cases where the 

sample had an oxygen concentration less than five percent

but a nitrogen concentration that was proportionally higher 

and would create a positive bias. (0013, 0019)

Response: We agree that the nitrogen correction for 

dilution would be more useful in Method 3C than Method 25C, 

and this has been done. We’ve noted that the equation may 

be used for oxygen correction by substituting values for 

oxygen in place of nitrogen.

Method 26

83. Comment: A commenter pointed out the difference in 

temperatures for the probe in the proposed change to 

Section 6.1.1 (248 ± 25°F) and that of Method 26A (greater 

than 248°F). This is also counter to the revised Section 

8.1.2 which also indicates a temperature of greater than 

248°F. (0015)

Response: We have clarified the language in both Method 26 

and Method 26A to be consistent with maintaining the 

temperature of the probe and filter between 120 and 134 C 

(248 and 273°F). Above this temperature range, we have 

evidence for positive bias from ammonium salts. Below this 

temperature range, moisture condensation is a concern. 

84. Comment: A commenter felt that in Section 6.1.1, the final 

sentence appears to be missing some language: “A 

Teflon‐glass filter in a mat configuration should be 

installed in the gas stream, not the filter box, to remove

particulate matter from the gas stream.” This sentence, as 

it stands, did not appear to signal the intent of the 
41

change desired. According to the proposal preamble, the 

intent was to indicate that the location of the 

thermocouple used to monitor the filter temperature should 

be in the gas stream. (0015)

Response: The commenter is correct. The amended language 

was out of place and is not in the final rule.

85. Comment: Another commenter took exception to the proposed 

language for Section 6.1.1. The commenter noted that a

Teflon filter or filter holder should not be installed in a 

high temperature gas stream and would be at odds with the

rest of the method, including the test train schematic. The 

commenter noted there is no benefit to doing so because 

that is the purpose of the heated filter box. (0035)

Response: The proposed language has not been included in 

the final rule.

86. Comment: A commenter asked if the new alternative 

procedure in Section 16 means Method 26A has to be 

conducted isokinetically when used in place of Method 26, 

or is it allowable to sample proportionally (such as a

fixed sampling rate of 0.75 CFM) at a single point as in 

Method 26 (i.e.: non-isokinetically) when the stack gas dew 

point is low and there is no chance of aerosol droplets. 

They requested clarification of this section. (0031)

Response: Method 26A implemented as written has been 

designated equivalent to Method 26. Method 26A remains an 

isokinetic method for initial and alternative applications 

unless specified otherwise in a specific regulation or 

rule.

87. Comment: A commenter supported the proposed revisions to 

Method 26 but was concerned with the change in the 

thermocouple location requirement and believed there were

more economical and practical means to prevent inaccurate 

temperature data. Noted alternatives included measuring the 

probe exit gas temperature in a dimple installed within 12 

inches of the probe end and physically attaching a 

thermocouple in the filter holder. These approaches would 

not require the temperature probe to be in the gas stream

nor would they incur the costs and small gains experienced 

by having the thermocouple in the gas stream. (0033, 0037)
42

Response: The proposed amendment addressing the location 

of the temperature sensor was in error and is not in the 

final rule. 

Method 29

88. Comment: A commenter supported the allowance for cold 

vapor atomic fluorescence spectrometry (CVAFS) as an 

alternative to the atomic absorption spectrometry (AAS)

analysis because it reflects the various analysis 

techniques that are available to the regulated industry. 

(0032)

Response: No response is necessary.

Method 30B

89. Comment: Three commenters wanted the sorbent trap 

alternative breakthrough criteria being allowed for 

relative accuracy test audits (RATAs) to also apply to 

compliance tests. They noted the difficulty in meeting the 

20 percent breakthrough limit for compliance samples when 

concentrations are below 0.5 μg/dscm. (0029, 0032, 0035)

Response: The alternative breakthrough criteria being 

allowed for RATAs are provided in part to address the 

difficulty in meeting the breakthrough criteria when 

sampling for the shorter run times (e.g., 30 minutes) often 

used in conducted RATA test runs. We understand that it may 

still be difficult to meet the 20 percent breakthrough 

criteria at very low mercury emission levels even with one 

or more hour run times used in compliance testing and have 

therefore provided some additional flexibility (though not 

all requested by the commenters) tied to the emissions 

limit level. An additional criterion will be added to Table 

9-1 as follows: "At mercury concentration levels at or 

below 30 percent of the Hg concentration that is equivalent 

to applicable emissions limit, the breakthrough criterion 

will now be < 50 percent of the section 1 Hg mass." In 

addition, based on further consideration of these comments 

as well as information we have received independently from 

at least one state currently implementing both Method 30B 

and Performance Specification 12B in a mercury control 

program, we are also making a revision to the breakthrough 

criteria in Performance Specification 12B to provide a 

similar flexibility at the extremely low concentrations 
43

currently being measured: "When mercury concentration level 

is less than or equal to 0.5 μg/scm, the breakthrough 

criterion will now be < 10 percent of the section 1 Hg mass 

rather than < 5 percent of the section 1 Hg mass and when 

the mercury concentration level is less than 10 percent of 

the emission standard, there will be no breakthrough 

criterion." This change will not affect data quality and 

will prevent invalidation of valid data at low 

concentrations.

90. Comment: The note to Section 8.2.4 currently states: “for 

the purposes of relative accuracy testing of Hg monitoring 

systems under part 75 of this chapter and Performance 

Specification 12A in appendix B to this part, when the 

stack gas Hg concentration is expected to be very low (<0.5 

μg/dscm) you may estimate the Hg concentration at 0.5 

μg/dscm.” A commenter recommended the reference to Part 75 

be deleted as Hg is no longer addressed in Part 75. More 

importantly, they believed the Part 75 reference should be 

replaced with a reference to Appendix A, Subpart UUUUU of 

Part 63. The reason is that in the EPA’s final Mercury and 

Air Toxics (MATS) rule affecting electric generating units, 

all requirements for Hg monitoring systems are contained in 

Appendix A; the MATS rule contains no reference to 

Performance Specification 12A. There is a similar reference 

to Part 75 in the note to Section 8.2.6.2 of Method 30B 

that should also be deleted and replaced with a reference 

to Appendix A, Subpart UUUUU. (0032)

Response: The EPA agrees with the commenter that the 

reference to part 75 should be deleted from the Notes in 

Sections 8.2.4 and 8.2.6.2 of Method 30B. The EPA also 

agrees that it would be appropriate to replace the 

reference to part 75 with a reference to Appendix A of 40 

CFR part 63, subpart UUUUU. The EPA notes that it would 

also be appropriate to reference Performance Specification 

12B in appendix B to part 60 in addition to Performance 

Specification 12A and has made all the above revisions to 

the final rule.

91. Comment: In the preamble to the proposed rule, the EPA 

states:

For compliance/emission testing, the specification in 

Table 9-1 for sample analysis would be revised to 

require analytical results be within the valid 

calibration range down to a concentration of 0.01 
44

μg/m3. This will ensure that measurements at the low 

levels being measured under recent rulemakings are of 

known, acceptable, and consistent quality.

A commenter noted that an inspection of Table 9-1 indicates 

that the EPA failed to make this revision. The commenter 

did not believe the EPA should unilaterally revise the 

sample analysis specification in Table 9-1. Rather, the 

sample analysis specification should be linked to where the 

Hg measurement is being made relative to the applicable 

emission limit. The commenter recommended that Table 9-1 be 

revised to require analytical results be within the valid 

calibration range whenever the concentration is equal to or 

greater than 50 percent of the applicable emission limit. 

As an example, if the Hg emission limit were 0.8 μg/dscm 

and the measured flue gas concentration is 0.4 μg/dscm, 

then the sample analysis would be required to fall within 

the valid calibration range of the analyzer. On the other 

hand, if the measured flue gas concentration were 0.2

μg/dscm relative to the 0.8 limit, there would be no 

justification for requiring additional sampling time and 

effort just to fall on the calibration curve. (0032)

Response: The EPA appreciates the commenter pointing out 

that it was the agency’s intent to include the proposed 

revision explained in the preamble as part of Table 9-1 and 

notes that it was our intent to include the referenced 

revision in Table 9-1. The EPA understands the commenter’s 

concern about having to sample for additional time just to 

ensure the sample results fall on the calibration curve 

when the emission levels measured are substantially below 

an emission limit. In response, in the final rule we have 

made a two-pronged revision to the proposed sample analysis 

criterion for compliance emission testing: (1) the general 

criterion has been doubled to 0.02 μg/dscm, and (2) an 

exception has been added to allow additional flexibility 

where the measured flue gas concentration is less than 30 

percent of the concentration that is equivalent to the 

applicable emission limit. We made the cutoff at 30 percent 

as opposed to 50 percent as suggested by the commenter to 

ensure data quality for a larger margin of compliance.

92. Comment: A commenter asked that we remove the reference to 

a mercury barometer from Section 10.4 to maintain 

consistency with the changes to Table 9-1. (0035)
45

Response: The EPA agrees with the commenter and revised the 

language in section 10.4 of Method 30B to make it 

consistent with that of Table 9-1.

PS-1

93. Comment: Two commenters objected to the note being added 

to Section 3.5 stating “full scale” means “span,” and 

recommended it be dropped. One commenter felt this was 

misleading and inaccurate because “full scale” of any COMS 

is 100 percent. The new definition may also be 

misrepresented for other pollutant analyzers. The commenter 

noted rules that have spans that are set at one level while 

the range of the instrument is at a higher level. They 

noted that this is also true for COMS where the COMS is 

spanned at a lower value (e.g. 40 or 60 percent) to improve 

the accuracy of the measurement near the opacity limit.

(0029, 0032)

Response: We agree with the commenters and have not made 

the amendment to Section 3.5.

94. Comment: A commenter was disappointed that the EPA did not 

correct the longstanding language problem in paragraphs 

8.1(2)(i) and 8.1(2)(ii). As the EPA previously 

acknowledged in a response to the Frequently Asked 

Questions (FAQ): “Paragraph 8.1(2)(i) should not limit the 

COMS locations to the four and two diameter sites, but 

instead should defer to 8.1(2)(ii) for additional options. 

Paragraph 8.1(2)(ii) is clear that you can install a COMS 

in a location that is not at least 4 duct diameters 

downstream and 2 duct diameters upstream of flow 

disturbances as long as you meet the appropriate 

requirements in the table of 8.1(2)(ii) and the associated 

figure. The commenter thought EPA should at least include 

its FAQ language somewhere in Section 8.1. (0032)

Response: The commenter’s suggestions are appreciated but 

are beyond the scope of the final rulemaking since they 

were not included in the proposal. These suggestions will 

be retained and will be considered in the next methods 

update package.

PS-3

95. Comment: A commenter supported the proposed amendment to

Section 12.2 to include a relative accuracy percentage 
46

criterion in addition to the mean difference criterion.

(0029, 0032)

Response: No response is necessary.

PS-4 and 4A

96. Comment: A commenter asked that it be made clear when 

Performance Specification 4 (PS-4) versus Performance 

Specification 4A (PS-4A) should be used. It should state 

that PS-4 is for CEMS with span values of 1000 ppm, and PS4A is primarily for CEMS with emission standards less than 

200 ppm. Guidance was sought on which PS is appropriate in 

the range between 200 and 1,000 ppm. (0029, 0032)

Response: The choosing of a performance specification 

between the measurement ranges of 200 and 1,000 ppm should 

be assessed and established during rulemaking. In cases 

where the applicable regulation is not clear, our 

recommendation is that either PS may be used and a specific 

span be chosen that is approximately twice the 

concentration of the emission standard or the average 

emissions concentration. Intervals of concentration spikes 

should also be considered. 

PS-7

97. Comment: In Section 8.4.2.1, A commenter recommended that 

the EPA not add the proposed statement that “Each sample 

shall be taken at approximately 30-minute intervals” to 

Section 8.4.2.1 for Methods 11, 15, and 16. The commenter

believed this would increase the duration and cost of the 

testing without improving the precision or the accuracy of 

the RATA results. (0035)

Response: We disagree with the commenter since sampling 

strategy and reference method tests are already addressed 

in referenced sections of Performance Specification 2 (PS2). Under PS-2, the 21-minute minimum sampling time was 

chosen considering grab samplers and non-instrumental 

samplers need time over the 30-minute test interval to 

switch out sampling systems. 

PS-11

98. Comment: A commenter asked that areas in Performance 

Specification 11 (PS-11) that are currently not clear be 
47

addressed in this rule. Section 8.4.6(4)(i) states that 

“you must attempt to obtain the three different levels of 

PM mass concentration by varying process operating 

conditions, varying PM control device conditions, or by 

means of PM spiking.” Section 8.6(5) states “if you cannot 

obtain three distinct levels of PM concentration, as 

described, you must perform correlation testing over the 

maximum range of concentrations that is practical for your 

PM.” The commenter did not believe there were reasonable 

means for increasing PM concentrations by varying either 

operating or control device conditions for utilities 

commonly using baghouse technology to control PM. The 

commenter believed the “you must attempt” language should 

be replaced with wording that obtaining three different PM 

concentrations is the preferred approach for correlating a 

PM CEMS, and Section 8.6(5) should be referenced as an 

acceptable alternative. (0032)

Response: These comments will be addressed separately in 

the upcoming PS-11 revisions and guidance rule.

99. Comment: Section 8.8(1) and (2) detail additional 

correlation testing if the CEMS responses are greater than 

125 percent of the highest PM CEMS response used for the 

correlation curve “while your source is operating under 

normal conditions.” The commenter believed that, by not 

providing a definition for “normal conditions,” it was 

unreasonable to require additional correlation testing when 

responses were greater than 125 percent as a result of 

start-up, shutdown, or malfunctions. It was noted that 

correlation testing is not performed during start-up, 

shutdown, or malfunction events, and it doesn’t make sense

to count responses greater than 125 percent that occur 

during such periods. (0029)

Response: These comments will be addressed in the upcoming 

PS-11 revisions and guidance rule.

PS-12B

100. Comment: A commenter noted that the references in Table 

12B-1 of Performance Specification 12B (PS-12B) of Appendix 

B to part 60 of 40 CFR to “Section 12.7.1.3” should be to 

“Section 12.8.3.” (0043)

Response: The EPA agrees with the commenter that the noted 

references in Table 12B-1 of PS-12B of Appendix B to part 
48

60 are incorrect. Though we did not propose any revisions 

to PS-12B in Appendix B to 40 CFR part 60 in this 

rulemaking, we believe this correction should be made and 

we are, therefore, revising Table 12B-1 of PS-12B to 

correct the references.

101. Comment: A commenter recommended that PS-12B address the 

consequences of data loss when one of sample sorbent traps 

is lost, broken, or damaged. The commenter noted that 

Performance Specification 12B was based on Appendix K of 

Part 75 which required the remaining good trap meet all 

applicable quality assurance requirements and the mercury 

concentration measured by that trap be multiplied by a 

factor of 1.111. The commenter recommended this language be 

added to PS-12B. (0043)

Response: Though we did not propose to make any revisions 

to PS-12B of Appendix B to 40 CFR part 60 in this 

rulemaking, we believe this is an addition that should be 

made to prevent invalidating data that are actually valid. 

As the commenter pointed out, PS-12B already includes 

provisions for using the results from a single sorbent trap 

when one of the two sorbent traps fails certain acceptance 

criteria, but it does not include a specific provision 

addressing the case where one trap is lost, broken, or 

damaged. We are, therefore, adding specific language to 

Section 12.8.3 of PS-12B to specifically address the case 

where one sample trap is lost, broken, or damaged.

102. Comment: In proposed and promulgated PS-12B, Table 12B-1, 

the ratio of stack gas flow rate to sample flow must not 

deviate by more that 25 percent from the ratio recorded in 

the first hour of data collection or the data must be 

invalidated. In the proposal, deviations up to five percent 

of the hourly ratios or 5 hourly ratios (whichever is less 

restrictive) were also allowed. A commenter believed this 

relief was needed to reduce the likelihood of complete data 

loss from both traps for periods of up to 14 operating 

days. It was noted that the EPA did not address why the 

allowance was not included in the final rule nor was there 

a negative public comment from its proposal. (0043)

Response: Though we did not propose to make any revisions 

to PS-12B of Appendix B to 40 CFR part 60 in this 

rulemaking, the EPA believes that the commenter makes a 

valid point that this minor flexibility that was dropped 

from the language between proposal and promulgation is 
49

warranted to avoid invalidating valid data. We are, 

therefore, incorporating the language into Table 12B-1 from 

the original proposal that allows for deviation from the 

proportional sampling reference ratio criteria of +25

percent for no more than five percent of the hourly values 

or 5 hourly ratios, whichever is less restrictive.

PS-15

103. Comment: A commenter noted that in updating Performance 

Specification 15 (PS-15) to reference the relative accuracy 

procedure in PS-2, no acceptability criteria for the 

relative accuracy test were given. A reference to Section 

13.0 of PS-2 was suggested. (0029, 0032)

Response: PS-15 references the relative accuracy 

procedures in PS-2 which includes the acceptance criteria.

PS-16

104. Comment: Three commenters supported the proposed changes 

in Section 13.5 of Performance Specification 16 (PS-16). 

Two believed the change would make it easier to meet the 

RAA requirements in the low concentration range. (0032, 

0033, 0037)

Response: No response is necessary.

Appendix F – Procedure 1

105. Comment: A commenter wanted Procedure 1 to be revised in 

this rulemaking. First, the commenter believed the cylinder 

gas audit (CGA) ranges allowed for diluent CEMS should be 

based on a percentage of instrument span and not just on an 

absolute cylinder gas concentration. Second, the commenter 

believed diluent CEMS should be allowed an accuracy of 15 

percent or ±0.5 percent O2 or CO2. Third, the commenter 

thought it helpful to revise Section 5.1.4 to allow for 

postponement of a RATA due to “limited operation (e.g., 

<168 hrs), and not just when the unit is not operating at 

all. (0029, 0032)

Response: The commenter’s suggestions are appreciated but 

are beyond the scope of the proposed revision to Procedure 

1. These suggestions will be retained and will be 

considered in the next methods update package.
50

Appendix F – Procedure 2

106. Comment: A commenter supports the proposed correction to 

the denominator of Equation 2-4 and believes the revision 

is consistent with EPA’s original intent. (0032)

Response: No response is necessary.

Method 101A

107. Comment: A commenter noted that proposed Section 16.1.2 

was mislabeled as 6.1.2. (0035)

Response: The commenter is correct, and this error has 

been corrected.

Method 107

108. Comment: One commenter asked that Method 107 also be 

revised in this rule although it was not revised in the 

proposal. The commenter desired that the calibration 

frequency be increased from the beginning and ending of an 

8-hr period to the beginning and ending of a 12-hr period. 

The commenter noted that the 8-hr period was chosen by 

their predecessor company to correspond to their 8-hr 

working shift. They felt a 12-hr period would better fit 

many of the employee shift schedules used in many 

manufacturing plants today. In a comparison study they 

performed, there was little average percent difference 

between calibrations performed over both intervals. (0041)

Response: This suggestion is significant enough to warrant 

a proposal for public comment. It will be catalogued for 

inclusion in the next rule to update and correct the 

method.

109. Comment: A commenter proposed an alternative method for 

determining total solids in Method 107. Currently, the 

method requires using a draft oven to dry resin samples. 

Microwave technology was believed to be the modern approach 

since it is faster than draft ovens and allows companies to 

more quickly determine the residual vinyl chloride content 

of resin in production and make the process adjustments 

necessary to maintain compliance. (0041)

Response: This suggestion is significant enough to warrant 

a proposal for public comment. It will be catalogued for 
51

inclusion in the next rule to update and correct the 

method.

Part 63 Subpart ZZZZ

110. Comment: A commenter believed the proposed revisions to 

Table 4 of the Stationary Reciprocating Internal Combustion 

Engines rule (Subpart ZZZZ) rule eliminated CO testing from 

Section 3 (Stationary RICE) as an option for performance 

testing. The commenter believed eliminating CO, and leaving 

formaldehyde (EPA Method 320) as the only option for 

performance testing would be costlier for sources, and may 

cause compliance issues for sources who have already taken 

a proactive approach and completed performance testing 

using CO as the compliance method. (0010)

Response: Carbon monoxide testing was not eliminated in 

the proposed rule. What was eliminated was Method 1 or 1A 

for determining the number of traverse points for CO 

measurement. It was replaced by sampling from the centroid 

of the exhaust.

Method 306

111. Comment: A commenter proposed the use of Teflon probe 

liners and the option to heat the probe to stack 

temperature. The commenter noted that many of the stacks 

are not strong enough to support equipment. Being able to 

heat the probe would help with testing in the winter time. 

(0012)

Response: The commenter’s suggestions are appreciated but 

are beyond the scope of the proposed revision to Method 

306. These suggestions will be retained and will be 

considered in the next methods update package.

Method 316 

112. Comment: One commenter strongly supports the use of Method 

316 as an alternative method for formaldehyde from mineral 

wool and wool fiberglass industries even though. (0038)

Response: No response is necessary.